Investigating the Gordian knot: how teaching assistants enact equitable and effective teaching during acid–base titrations

Laboratory teaching assistants (TAs) crucially shape undergraduates' chemistry learning experiences. However, akin to the Gordian knot metaphor ( i.e. , an intractable problem near impossible to solve), TA pedagogy is intricate and difficult to support by conventional means. More attention is needed to discern the complexities of enacted TA pedagogies and their alignment with equitable and effective teaching. Using Teacher Noticing, Multidimensional Noticing, and teaching for Meaningful Learning, this study involved two focal TAs, Alexandra and Bred, as a comparative case study. We used video research principles and video-stimulated recall interviews to qualitatively investigate how participants' teach acid–base titrations. Our findings indicate that TA efforts related to equitable and effective instructional moves can be both complementary and conflicting. Surprisingly, TAs may actually be the ones meaningfully learning in place of their students. Implications include suggestions for long-term training programs (video club and instructional coaching) that invite TAs to analyse students’ learning via enacted pedagogies. We offer specific, accessible, and practical suggestions to foreground particulate-level interactions, sensemaking, local agriculture, nutrition, and university life when teaching acid–base chemistry. We thus invite our community to interrogate and reimagine what we want as evidence of learning and of teaching to inform shifts in instructional laboratory culture.